The purpose of this study will be to screen potential agents for use in the chemotherapy of brain tumors and to evaluate the immune status of patients with brain tumors. The methods will involve the use of a virus-induced glioma model and the screening of anti-tumor drugs for effectiveness in this system. As regards evaluation of the immune status of glioma patients, a tissue culture facility will be established. As part of the activities of that laboratory, in vitro studies will be performed with glioma patient serum and lymphocytes, to assay any humoral or cellular cytotoxicity against the glioma in tissue culture; evidence of the presence of serum blocking antibodies will also be sought.